1. Field of the Invention
The present disclosure relates to a wiring substrate using ceramic and a light emitting device including the wiring substrate.
2. Description of the Related Art
Low temperature co-fired ceramics substrates (hereinafter, referred to as “LTCC substrates”) have been known as a wiring substrate for a light emitting device including a semiconductor light emitting element (hereinafter, also referred to as a “light emitting element”). Since an LTCC substrate is more inexpensive than a high temperature fired ceramics substrate made of aluminum nitride or the like, a reduction in cost can be expected.
It has been known that silver is used for a conductive layer of an LTCC substrate. Moreover, it has been known that a glass layer is provided on a surface of the conductive layer provided on an upper surface of the LTCC substrate, in order to prevent corrosion of silver.
For example, see JP 2011-228672 A.
However, a glass layer provided as described above is occasionally unsatisfactory for suppressing discoloration of a wiring substrate due to silver.